Dye adsorption device, dye adsorption method and substrate treatment apparatus

ABSTRACT

[Problem] To significantly reduce processing time of a step of adsorbing dye in a porous semiconductor layer on a substrate surface. 
     [Solution] A flow of a dye solution is formed in a gap between solution guide surface ( 92 L,  92 R) of a nozzle ( 20 ) and a substrate (G) during the treatment, and a porous semiconductor layer of a treated surface of the substrate is subject to dye adsorption treatment in this flow of the dye solution. Furthermore, impact pressure from slit-like discharge openings ( 88 L,  88 R) and pressure of turbulent flow in groove-like uneven sections ( 92 L,  92 R) act in the vertical direction in addition to the flow of the dye solution. Thus, aggregation and association of the dye are hardly caused on a surface part of the porous semiconductor layer of the treated surface of the substrate, the dye efficiently penetrates deeply into the porous semiconductor layer, and the dye adsorption into the porous semiconductor layer proceeds at high speed.

TECHNICAL FIELD

The present invention relates to a dye adsorption device, a dyeadsorption method and a substrate treatment apparatus for adsorbing adye into a porous semiconductor layer formed on a surface of asubstrate.

BACKGROUND

Recently, a dye sensitization solar cell has been considered aspromising as a future inexpensive solar cell. As illustrated in FIG. 20,a dye sensitization solar cell includes, as a basic structure, a poroussemiconductor layer 204 impregnated with a sensitizing dye and anelectrolyte layer 206 between a transparent electrode (negativeelectrode) 200 and a counter electrode (positive electrode) 202.

Here, the semiconductor layer 204 is divided into a plurality of cellstogether with the transparent electrode 200, the electrolyte layer 206,and the counter electrode 202, and formed on a transparent substrate 208in which the transparent electrode 200 is interposed between thesemiconductor layer 204 and the transparent substrate 208. The rearsurface side of the counter electrode 202 is covered with a countersubstrate 210. The transparent electrode 200 of each cell iselectrically connected with a neighboring counter electrode 202 and theplurality of cells are electrically connected with each other either inseries or in parallel in an entire module.

In the dye sensitization solar cell configured as described above, whenvisible light is illuminated from the rear surface side of thetransparent substrate 208, the dye impregnated in the semiconductorlayer 204 is excited to emit electrons. The emitted electrons are guidedto the transparent electrode 200 through the semiconductor layer 204 andthen emitted to the outside. The emitted electrons return to the counterelectrode 202 via an external circuit (not illustrated) and are receivedin the dye in the semiconductor layer 204 again through the ions in theelectrolyte layer 206. In this manner, optical energy is immediatelyconverted into electric power which is in turn output.

In a process of fabricating such a dye sensitization solar cell, amethod of immersing the porous semiconductor layer 204 formed on thetransparent substrate 208 in a dye solution so as to adsorb asensitizing dye into the porous semiconductor layer 204 has beenemployed in the related art.

PRIOR ART DOCUMENT Patent Document

-   Patent Document 1: Japanese Patent Laid-Open Publication No.    2006-244954

DISCLOSURE OF THE INVENTION Problem to be Solved by the Invention

The above-described immersing method requires at least scores of hoursin the dye adsorption processing which may vary depending on the typesof the dye and thus, becomes the cause of rate-determining of tact ofthe entire steps in a process of fabricating a dye sensitization solarcell and decreasing manufacturing efficiency. In connection with thisproblem, it may be considered to operate a plurality of immersion typedye adsorption devices in parallel which requires at least scores of dyeadsorption devices to be prepared, which is not practical.

The present invention has been made to solve the problems of the relatedart as described above and provides a dye adsorption device and a dyeadsorption method capable of significantly reducing the amount ofprocessing time in a step of adsorbing dye into a porous semiconductorlayer formed on a treated surface of a substrate.

Also, the present invention provides a substrate treatment apparatuscapable of significantly reducing the amount of processing time in astep of adsorbing dye into a porous semiconductor layer formed on asurface to be treated (“treated surface”) of a substrate, andefficiently preventing or suppressing aggregation and precipitation ofthe dye.

Means to Solve the Problems

A dye absorption apparatus according to the present invention is anapparatus of adsorbing a dye into a porous semiconductor layer formed ona treated surface of a substrate. The apparatus includes: a holding unitconfigured to hold the substrate such that the treated surface of thesubstrate faces upward; a nozzle having an ejection port and disposedabove the holding unit so that the ejection port faces downward; and adye solution supply unit configured to pump a dye solution formed bysolving the dye in a predetermined solvent to the nozzle. The dyesolution is ejected from the ejection port of the nozzle to the treatedsurface of the substrate held on the holding unit through a first gap sothat a flow of the dye solution is formed on the treated surface of thesubstrate and the dye contained in the dye solution is adsorbed into thesemiconductor layer.

A dye adsorption method according to the present invention is a methodof adsorbing a dye into a porous semiconductor layer formed on a treatedsurface of a substrate. The method includes: disposing the substrate ata predetermined position such that the treated surface of the substratefaces upward; positioning the nozzle to be opposed to the substrate;pumping a dye solution formed by solving the dye in a predeterminedsolvent to the nozzle and ejecting the dye solution from the ejectionport of the nozzle to the treated surface of the substrate held on theholding unit through a first gap so that a flow of the dye solution isformed on the treated surface of the substrate and the dye contained inthe dye solution is adsorbed into the semiconductor layer.

In the dye adsorption device or method of the present invention, a flowof the dye solution is formed in the gap between the guide surface ofthe nozzle and the substrate during the processing, and the poroussemiconductor layer of the treated surface of the substrate is subjectto a dye adsorption processing in the flow of the dye solution. Also, inaddition to the flow of the dye solution, impact pressure from theejection port acts in the vertical direction. Thus, aggregation orcohesion of the dye is hardly caused on a surface layer portion of theporous semiconductor layer, the dye may efficiently penetrate deeplyinto the porous semiconductor layer, and the dye adsorption into theporous semiconductor layer may proceed at high speed.

According to an aspect of the present invention, an uneven section isformed on the solution guide surface of the nozzle so that whirlpool orturbulent flow is formed in the dye solution on the uneven section.Thus, it becomes easier for the dye solution to penetrate deeply intothe treated surface (porous semiconductor layer) of the substrate.

Further, according to an aspect of the present invention, there isprovided a suction section which is positioned at a trailing end of theflow of the dye solution on the substrate to suck in the dye solution.Preferably, the suction section includes a suction port formed on thebottom surface of the nozzle and a vacuum passage formed within thenozzle. By the suction action of the suction section, the flow of thedye solution may be smoothly formed on the substrate, and the dyeadsorption may be further facilitated.

A substrate treatment apparatus according to the present inventionincludes: a holding unit configured to hold a substrate formed with aporous semiconductor treated surface such that the treated surface facesupward; a dye adsorption unit configured to adsorb dye to thesemiconductor layer of the substrate held on the holding unit; and arinse unit configured to wash out extra dye from a surface of thesemiconductor layer of the substrate. The dye adsorption unit includes:a first nozzle having an ejection port and disposed above the holdingunit such that the ejection port faces downward, and a dye solutionsupply unit configured to pump dye solution in which the dye is solvedin a predetermined solvent to the first nozzle. The dye solution isejected from the ejection port of the nozzle to the treated surface ofthe substrate held on the holding unit through a first gap to form aflow of the dye solution on the treated surface of the substrate and toadsorb the dye contained in the dye solution into the semiconductorlayer.

In the substrate treatment apparatus of the present invention, a flow ofdye solution is formed in a gap between the guide surface of the nozzleand the substrate during the dye adsorption processing, the poroussemiconductor layer of the treated surface of the substrate is subjectto dye adsorption processing in the flow of the dye solution. Also, inaddition to the flow of the dye solution, impact pressure from theejection port acts in the vertical direction. Thus, aggregation orcohesion of dye is hardly caused on a surface layer portion of theporous semiconductor layer, the dye may efficiently penetrate deeplyinto the porous semiconductor layer, and the dye adsorption into theporous semiconductor layer may proceed at high speed. Further, a rinseprocessing is performed following the dye adsorption processing toremove extra dye from the surface of the semiconductor layer on thesubstrate. Thus, the cohesion and precipitation of dye on a surfacelayer portion of the porous semiconductor layer may be efficientlyprevented or suppressed.

Effect of the Invention

According to the dye adsorption device or dye adsorption method of thepresent invention, a processing time in a step of adsorbing dye into aporous semiconductor layer on a treated surface of a substrate may besignificantly reduced by the configurations and actions as describedabove.

In addition, according to the substrate treatment apparatus of thepresent invention, processing time in a step of adsorbing dye into aporous semiconductor layer on a treated surface of a substrate may besignificantly reduced and the cohesion and precipitation of dye on asurface layer portion of the porous semiconductor layer may beefficiently prevented or suppressed by the configurations and actions asdescribed above.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view illustrating a configuration of a dyeadsorption device according to an exemplary embodiment of the presentinvention.

FIG. 2 is a plan view illustrating a principal portion of the dyeadsorption device.

FIG. 3A is a perspective view illustrating a configuration of aprincipal portion of a nozzle in the dye adsorption device.

FIG. 3B is a longitudinal sectional view illustrating the principalportion of the nozzle.

FIG. 4 is a cross-sectional view for schematically describing actions inthe dye adsorption device in the vicinity of the surface of thesubstrate.

FIG. 5 is a view illustrating a size requirement in groove-like unevensections.

FIG. 6 is a perspective view illustrating a state in which the nozzlestands by on the standby bus.

FIG. 7 is a longitudinal sectional view illustrating the state of thenozzle standing by on the standby bus.

FIG. 8 is a cross-sectional view illustrating a configuration of asubstrate treatment apparatus according to an exemplary embodiment ofthe present invention.

FIG. 9A is a perspective view illustrating a modified example of thegroove-like uneven sections of the nozzle.

FIG. 9B is a longitudinal sectional view illustrating the configurationof the nozzle of FIG. 9A.

FIG. 10 is a perspective view illustrating a modified example of theejection passage and the ejection port of the nozzle.

FIG. 11 is a longitudinal sectional view illustrating a modified exampleof the groove-like uneven sections of the nozzle.

FIG. 12 is a longitudinal sectional view illustrating a modified exampleof the ejection section and the suction section of the nozzle.

FIG. 13A is a perspective view illustrating an exemplary embodiment inwhich the groove-like uneven sections are omitted in the nozzle.

FIG. 13B is a longitudinal sectional view illustrating a principal partof the nozzle of FIG. 13A.

FIG. 14A is a perspective view illustrating an exemplary embodiment inwhich the suction section is omitted in the nozzle.

FIG. 14B is a longitudinal sectional view illustrating a configurationof a principal part of the nozzle of FIG. 14.

FIG. 15A is a perspective view illustrating an exemplary embodiment inwhich the suction section is omitted in the nozzle of FIG. 15A.

FIG. 15B is a longitudinal sectional view illustrating a configurationof a principal part of the nozzle of FIG. 15A.

FIG. 16A is a time-pressure diagram representing a method of varying theejecting pressure of the nozzle during the treatment.

FIG. 16B is a time-pressure diagram representing another method ofvarying the ejecting pressure of the nozzle during the treatment.

FIG. 17 is a plan view illustrating an exemplary embodiment in which thenozzle is formed to have a size to cover the substrate.

FIG. 18 is a plan view illustrating an exemplary embodiment in which thenozzle is formed in a disc shape.

FIG. 19 is a plan view illustrating an exemplary embodiment in which thesubstrate is rectilinearly moved or reciprocated during the treatment.

FIG. 20 is a longitudinal sectional view illustrating a basic structureof a dye sensitization solar cell.

DETAILED DESCRIPTION TO EXECUTE THE INVENTION

Hereinbelow, exemplary embodiments of the present invention will bedescribed with reference to FIGS. 1 to 19.

Exemplary Embodiment 1

FIGS. 1 and 2 illustrate the entire configuration of the dye adsorptiondevice according to an exemplary embodiment of the present invention.The dye adsorption device may be used, for example, in a step ofadsorbing sensitizing dye into a porous semiconductor layer in a singlewafer type in a process of fabricating a dye sensitization solar cell.In such a case, a transparent substrate formed with a transparentelectrode 200 and a porous semiconductor layer 204 before counterpartmembers (a counter electrode 202, a counter substrate 210 and anelectrolyte layer 206) are combined (FIG. 20) will be a treatedsubstrate G in the dye adsorption device.

Here, the transparent substrate 208 is made up of, for example, atransparent inorganic material such as, for example, quartz or glass, ora transparent plastic material such as, for example, polyester, acryl orpolyimide. The transparent electrode 200 is made up of, for example,fluorine doped SnO₂ (FTO) or indium-tin oxide (ITO). In addition, theporous semiconductor layer 204 may be made up of, for example, a metaloxide such as, for example, TiO₂, ZnO or SnO₂. The substrate G has apredetermined shape (e.g., a quadrilateral shape) and a predeterminedsize and is carried into/carried out from the dye adsorption device by atransport robot (not illustrated).

As illustrated in FIGS. 1 and 2, the dye adsorption device includes aprocessing chamber 10 capable of being opened to an atmospheric space,and a substrate holding unit 12 is installed at a central part of theprocessing chamber 10. The substrate holding unit 12 includes a chuckplate 14 of a disc shape configured as a spin chuck to hold thesubstrate G to be rotatable horizontally and having a diameter smallerthan the length of a smaller side of the substrate G, and a driving unit18 configured to rotationally drive the chuck plate 14 in thecircumferential direction through a rotating support shaft 16.

For example, concentric and/or radial grooves are formed on the topsurface (substrate placement surface) of the chuck plate 14 andconnected to a negative pressure source, for example, a vacuum pump (notillustrated) through a vacuum passage that extends through the interiorof the rotating support shaft 16 and the driving unit 18. When thesubstrate G is placed on the chuck plate 14 in a state where the treatedsurface formed with the semiconductor layer 204 faces upward, negativepressure from the negative pressure source is imparted to each of thegrooves on the top surface of the chuck plate 14, and suction force ofnegative pressure acts on the rear surface of the substrate G from eachof the grooves, thereby fixing and holding the substrate G on the chuckplate 14. The substrate holding unit 12 is provided with a lift pinmechanism (not illustrated) configured to raise or lower the substrate Gon the chuck plate 14 at the time of carrying-in/carrying-out of thesubstrate G.

An opening (not illustrated) configured to be capable of beingopened/closed is formed in a side wall 10 a of the processing chamber10. The top cover 10 b of the processing chamber 10 is formed with aplurality of vent holes (not illustrated) so as to introduce clean airinto the chamber from the outside. Alternatively, the top side may beentirely opened without the top cover 10 b, or a fan filter unit (FFU)may be installed on the ceiling of the processing chamber 10.

In the inside of the processing chamber 10, a movable nozzle 20 isinstalled above the substrate holding unit 12. The nozzle 20 isconfigured to be supported horizontally and to be movable horizontallybetween a processing position P₁ set on the chuck plate 14 and a standbyposition P₂ on a standby bus 26 installed next to the chuck plate 14 bya nozzle movement mechanism 22 installed in the outside of theprocessing chamber 10 and via an arm 24. The nozzle movement mechanism22 includes a rectilinear driving mechanism such as, for example, aball-screw mechanism or a linear motor, and further includes a liftmechanism that varies or adjusts the height position of the nozzle 20 inthe vertical direction.

As described below in detail, the nozzle 20 includes an ejection section28 configured to eject dye solution onto the substrate G and suctionsections 30L, 30R configured to suck in the dye solution from thesubstrate G. One or more inlet ports 33 configured to introduce dyesolution sent from a dye solution supply unit 32 into the ejectionsection 28 and one or more outlet ports 36L, 36R configured to dischargethe dye solution sucked in from the suction sections 30L, 30R to theoutside of the nozzle 20 so as to send the dye solution to a dyesolution recovery unit 34 are provided on the top surface of the nozzle20.

The dye solution supply unit 32 includes a tank 38 configured to storethe dye solution, a dye solution supply line 40 configured by, forexample, a pipe configured to connect the tank 38 and the inlet ports 33of the nozzle, an electromagnetic open/close valve 42, a supply pump 44,and an electromagnetic proportion valve 46. The electromagneticopen/close valve 42, the supply pump 44, and the electromagneticproportion valve 46 are provided on the way of the dye solution supplyline 40. The electromagnetic proportion valve 46 is used in order tovariably control or adjust the pressure or flow rate of the dye solutiondrawn up from the tank 38 and pumped to the nozzle 20 by the supply pump44.

A thermostat 48 is attached to the tank 38 to adjust the temperature ofthe dye solution to a predetermined treatment temperature which issuitable for dye adsorption processing. Also, a new solution supply pipe52 from the dye solution supply source 50 and a regenerated solutionsupply pipe 54 from a dye solution recover unit 34 to be described areconnected to the tank 38 so as to replenish the tank 38 with dyesolution.

In addition, the dye solution used in the dye adsorption device isformed by solving sensitizing dye in a solvent with a predeterminedconcentration. As for the sensitizing dye, for example, a metal complexsuch as, for example, metal phthalocyanine, or an organic dye such as,for example, a cyanine-based dye or a basic dye may be used. As for thesolvent, for example, alcohols, ethers, amides, or a hydrocarbon may beused.

The dye solution recovery unit 34 includes a suction pump 58 configuredto suck in and send the dye solution together with air to a dye solutiontrap 56, a vacuum line 60 configured by, for example, a pipe configuredto connect the inlet side of the suction pump 58 and the outlet ports36L, 36R of the suction pump 58, an electromagnetic proportion valve 62,and an electromagnetic open/close valve 64 in which the electromagneticproportion valve 62 and the electromagnetic open/close valve 64 areprovided on the way of the vacuum line 60. The electromagneticproportion valve 64 is used in order to variably control or adjust thenegative pressure discharging the dye solution from the outlet ports36L, 36R of the nozzle 20 or the flow rate of the dye solutiondischarged from the outlet ports 36L, 36R of the nozzle 20.

The dye solution trap 56 collects the recovered dye solution sent fromthe outlet side of the suction pump 58 together with air in a trapmember by, for example, a labyrinth method or a cyclone method, andsends the recovered and collected dye solution to a dye solutionregenerative unit 66. The dye solution regenerative unit 66 includes,for example, a filter and a concentration adjustment unit, and producesthe regenerated dye solution that has a component and a concentrationwhich are substantially the same as those of new dye solution from therecovered dye solution. An electromagnetic open/close valve 68 and apump 70 are provided on the way of the regenerated solution supply pipe54 that interconnects the dye solution regenerative unit 66 and the tank38 so that the regenerated dye solution may be frequently supplied tothe tank 38 from the dye solution regenerative unit 66 through theregenerated solution supply pipe 54. In addition, the electromagneticopen/close valve 51 is also provided on the way of the new solutionsupply pipe 52 so that the new dye solution may be frequently suppliedto the tank 38 from the dye solution supply source 50 through the newsolution supply pipe 52. In this manner, the reuse of the dye solutionis enabled and thus, the consumption of new dye solution may be reduced.

One or more exhaust/drain ports 72 are formed on the bottom surface ofthe processing chamber 10 and connected to the inlet side of the suctionpump 58 through an exhaust/drain line 74 configured by, for example, apipe. An electromagnetic open/close valve 76 is provided on the way ofthe exhaust/drain line 74.

In addition, an exhaust line 78 is also connected to a standby bus 26 tobe described later. The exhaust line 78 may be connected to the inletside of the suction pump 58 but is preferably connected to a separateexhaust pump (not illustrated). An electromagnetic open/close valve 80is also provided on the way of the exhaust line 78.

A controller 82 includes a microcomputer and an interface as needed,controls each unit in the dye adsorption device, and further controlsthe sequence of the entire apparatus that executes the dye adsorptionprocessing.

Here, the configuration of the nozzle 20 is described in detail. Asillustrated in FIG. 2, the nozzle 20 is an elongated nozzle extending ina horizontal direction (Y direction) orthogonal to a horizontal movementdirection (X direction) and preferably has the whole length longer thana diagonal line of the substrate G.

As illustrated in FIG. 3A, the ejection section 28 of the nozzle 20includes a tunnel-like buffer chamber (manifold) 84 extending in thelongitudinal direction of the nozzle (Y direction) at the center of thenozzle 20, a pair of slit-like ejection passages 86L, 86R divided intotwo from the bottom of the buffer chamber 84 and extending obliquelydownward, slit-like ejection ports 88L, 88R formed at the trailing endsof these slit-like ejection passages 86L, 86R, respectively, and aslit-like solution inlet passage 90 extending vertically upward from thetop of the buffer chamber 84 to the inlet port 33 (FIGS. 1 and 2).

The lower surface of the nozzle 20 extends from both the ejection ports88L, 88R to the left and right outsides in the widthwise direction (Xdirection), thereby forming guide surfaces 92L, 92R. The guide surfaces92L, 92R are formed with one or more groove-like uneven sections 94L,94R (three in the illustrated exemplary embodiment) which extend in thelongitudinal direction of the nozzle (Y direction) in parallel to theslit-like ejection ports 88L, 88R.

In addition, in the outside of the groove-like uneven sections 94L, 94R,suction ports 96L, 96R of the suction sections 30L, 30R which alsoextend in the longitudinal direction of the nozzle in parallel to theslit-like ejection ports 88L, 88R are formed on the guide surfaces 92L,92R, respectively. The pair of left and right suction ports 96L, 96R areconnected to the outlet ports 36L, 36R, respectively, through slit-likelower vacuum passages 98L, 98R, tunnel-like buffer chambers (manifolds)100L, 100R, and slit-like upper vacuum passages 102L, 102R which areformed in the inside of the nozzle 20 (FIG. 7).

Next, the actions of the dye adsorption device of the present exemplaryembodiment will be described.

The substrate G is carried into the processing chamber 10 and placed onthe chuck plate 14 of the substrate holding unit 12 by a transportrobot. Just after this, the nozzle movement mechanism 22 is operated tomove the nozzle 20 in the X direction from the standby position P₂ onthe nozzle standby unit 26 to the processing position P₁ on the chuckplate 14. In this processing position P₁, the bottom surface of thenozzle 20, in particular, the nozzle ejection ports 88L, 88R and thegroove-like uneven sections 94L, 94R are opposed to the substrate G onthe chuck plate 14 through a defined gap.

Subsequently, the dye solution supply unit 32, the dye solution recoveryunit 34 and the driving unit 18 of the substrate holding unit 12 areoperated to initiate the dye adsorption processing.

In the dye solution supply unit 32, the electromagnetic open/close valve42 is opened and the supply pump 44 is operated so that the dye solutionis sent from tank 38 to the inlet port 33 of the nozzle 20 through thedye solution supply line 40 at a predetermined flow rate. In the nozzle20, the dye solution introduced into the inlet port 33 enters into thebuffer chamber 84 through the solution inlet passage 90, passes throughthe solution ejection passages 86L, 86R, and then is ejected fromslit-like ejection ports 88L, 88R onto the substrate G. As the dyesolution is ejected onto the substrate G from the slit-like ejectionport 88L, 88R, the dye solution compressively contacts with the treatedsurface (porous semiconductor layer 204) of the substrate G with apredetermined impact force.

In addition, the dye solution ejected onto the substrate G from both theejection ports 88L, 88R flows toward the left and right outsides, i.e.,toward the suction ports 96L, 96R along the left and right guidesurfaces 92L, 92R, as illustrated in FIG. 3B. At this time, asillustrated in FIG. 4, whirlpool or turbulent flow in the verticaldirection is generated in the flow of the dye solution by thegroove-like uneven sections 94L, 94R of the guide surfaces 92L, 92R andthus, the contact pressure of the dye solution in relation to thetreated surface (porous semiconductor layer 204) of the substrate G maybe increased.

After passing through the groove-like uneven sections 94L, 94R, the dyesolution is sucked into the suction ports 96L, 96R. In the dye solutionrecovery unit 34, the electromagnetic open/close valve 64 is opened andthe suction pump 58 is operated, the dye solution sucked into thesuction sections 30L, 30R of the nozzle 20 from the top side of thesubstrate G is recovered through the outlet ports 36L, 36R of the nozzle20 and the vacuum line 60.

The driving unit 18 of the substrate holding unit 12 rotates thesubstrate G integrally with the chuck plate 14 at a predeterminedrotation speed in the circumferential direction or azimuthal directionduring the processing. With this rotation of the substrate G, the flowof the dye solution may reach every part on the entire treated surfaceof the substrate G. Also, a point where the movement of the substrate Gis in a forward direction in relation to the flow of the dye solutionand a point where the movement of the substrate G is in a reversedirection in relation to the flow of the dye solution occur on thetreated surface of the substrate G. In order to reduce the variation ofthe relative velocity between the flow of the dye solution and themovement of the substrate G, it is desirable to rotate the substrate Gat a low speed (e.g., about 1 ppm to 10 ppm).

In addition, when the ejection ports 88L, 88R of the nozzle protrude tothe outside of the substrate G while the substrate G is being rotated,the dye solution ejected from the ejection ports 88L, 88R is scatteredaround the substrate G. However, the scattered dye solution is collectedto the bottom of the processing chamber 10 and recovered to the dyesolution recovery unit 32 from the exhaust/drain port 72.

As described above, in the present exemplary embodiment, a flow of thedye solution is formed in the gap between the guide surfaces 92L, 92R ofthe nozzle 20 and the substrate G, and the porous semiconductor layer204 of the treated surface of the substrate G is subject to a dyeadsorption processing in this flow of the dye solution. Further, inaddition to the flow of the dye solution, impact pressure from theslit-like ejection ports 88L, 88R and the pressure of turbulent flow inthe groove-like uneven sections 94L, 94R act in the vertical direction.Thus, aggregation or cohesion of the dye is hardly caused on the surfacelayer portion of the porous semiconductor layer 204, the dye efficientlypenetrates deeply into the porous semiconductor layer 204, and the dyeadsorption into the porous semiconductor layer 204 proceeds at highspeed. When the method of the present exemplary embodiment is used, thedye adsorption processing time in a process of fabricating a dyesensitization solar cell may be significantly shortened, and finished,for example, within 10 minutes.

In the present exemplary embodiment, it is required to form thegroove-like uneven sections 94L, 94R with a proper size in order togenerate the turbulent flow of the dye in the groove-like unevensections 94L, 94R of the nozzle efficiently, stably and securely asdescribed above. According to the repeated experiments performed by theinventor, assuming that the gap size (a set value) between the guidesurfaces 92R(92L) and the substrate G is S_(a) as illustrated in FIG. 5,it has been found out that the width W of the groove-like unevensections 94R(94L) may be selected preferably in the range of 0.3S_(a) to1.5S_(a), and the most preferable effect may be obtained in the range of0.5S_(a) to 1.0S_(a). In addition, it has been found out that the depthD of the groove-like uneven sections 94R(94L) may also be selectedpreferably in the range of 0.3S_(a) to 1.5S_(a), and the most preferablyin the range of 0.5S_(a) to 1.0S_(a).

In addition, since ejecting pressure imparted to the treated surface ofthe substrate G from both the ejection ports 88L, 88R of the nozzle 20is also important as described above, the gap size S_(b) between boththe ejection ports 88R(88L) and the substrate G may be optimizedindependently from the gap size of the solution guide surface 92R(92L)size, and the slit width K may be preferably selected in a proper size.However, the slit width K may be typically selected to be Sb≈K≈Sa.

The dye adsorption processing in the present exemplary embodiment isended as the dye solution supply unit 32, the dye solution recovery unit34 and the driving unit 18 of the substrate holding unit 12 are stoppedafter the predetermined time elapses. Just after this, the nozzlemovement mechanism 22 is operated to move the nozzle 20 from theprocessing position P₁ on the chuck plate 14 to the standby position P₂on the nozzle standby unit 26. The substrate holding unit 12 releasesthe adsorptive holding of the substrate G on the chuck plate 14, liftsthe substrate G upward from the chuck plate 14 by the lift pin mechanismto hand the substrate G over to the transport robot.

As illustrated in FIGS. 6 and 7, the nozzle standby unit 26 isconfigured as an elongated solvent storage unit having a top sideopening 104 corresponding to the nozzle 20. While the nozzle 20 isstanding by on the nozzle standby unit 26, the ejection ports 88L, 88R,the groove-like uneven sections 94L, 94R and the suction ports 96L, 96Ron the bottom surface of the nozzle 20 are exposed to the vapor of thesolvent within the nozzle standby unit 26. Thus, blockage does notoccur.

In addition, while the nozzle 20 is being spaced apart from the nozzlestandby unit 26, the open/close valve 80 of the exhaust line 78 (FIG. 1)is opened so that local exhaust within the nozzle standby unit 26 isperformed. Thus, vapors of the solvent 106 from the nozzle standby unit26 do not leak to the surroundings.

Exemplary Embodiment 2

FIG. 8 illustrates the entire configuration of a substrate treatmentapparatus according to the second exemplary embodiment of the presentinvention. In the drawing, the components having the same configurationor function as those of the first exemplary embodiment (FIGS. 1 to 7)will be denoted by the same symbols.

The substrate treatment apparatus includes, as a dye adsorption unit,the dye adsorption device of the first exemplary embodiment as it is,and further includes a rinse unit and a dry unit. In the presentexemplary embodiment, the rinse unit includes a substrate holding unit12, a nozzle 20, a rinse solution supply unit 110, and a rinse solutionrecovery unit 112. Here, the substrate holding unit 12 and the nozzle 20are used in the rinse unit and the dry unit as well as in the dyeadsorption unit. In addition, the suction pump 58, the vacuum line 60,the electromagnetic proportion valve 62, and the electromagneticopen/close valve 64 are shared between the dye solution recovery unit 34of the dye adsorption unit and the rinse solution recovery unit of therinse unit.

The rinse solution supply unit 110 includes: a tank 114 configured tostore rinse solution; a rinse solution supply line 116 configured tosupply the rinse solution from the tank 114 to the nozzle 20 and formedby, for example, a pipe; an electromagnetic open/close valve 118; asupply pump 120; and an electromagnetic proportion valve 122 in whichthe electromagnetic open/close valve 118, the supply pump 120, and theelectromagnetic proportion valve 122 are provided on the way of therinse solution supply line 116. The electromagnetic proportion valve 122is used in order to variably control or adjust the pressure or flow rateof the rinse solution drawn up from the tank 114 and pumped to thenozzle 20 by the supply pump 120.

A new solution supply pipe 126 from the rinse solution supply source 124and a rinse solution recovery pipe 128 from the rinse solution recoveryunit 112 are connected to the tank 114 in order to replenish the tank114 with the rinse solution. An electromagnetic open/close valve 130 isprovided on the way of the new solution supply pipe 126 to be capable offrequently supplying the new rinse solution from the rinse solutionsupply source 124 to the tank 114 through the new solution supply pipe126. The rinse solution recovery unit 112 is provided with a filter 132on the way of the rinse solution recovery pipe 128 to remove dirt orimpurity. The rinse solution may be any liquid in which a sensitizingdye is solved and, for example, alcohols, ethers, amides and ahydrocarbon may be properly used.

In the present exemplary embodiment, in order to allow the nozzle 20 tobe shared among the dye adsorption unit, the rinse unit and the dryunit, a first switching unit 134 including, for example, a directioncontrol valve is provided, the inlet port 33 of the nozzle 20 isconnected to an output port of the first switching unit 134 through acommon fluid supply line 136 formed by, for example, a pipe, and the dyesolution supply line 40, the rinse solution supply line 116 and atailing end of a gas supply line 148 from the dry unit to be describedlater are connected to three input ports of the switching unit 134,respectively.

In addition, in order to allow the suction pump 58, the vacuum line 60,the electromagnetic proportion valve 62, and the electromagneticopen/close valve 64 to be shared between the dye solution recovery unit34 of the dye adsorption unit and the rinse solution recovery unit 112of the rinse unit, a second switching unit 138 including, for example, adirection control valve is provided, the outlet side of the suction pump58 is connected to an input port of the second switching unit 138through a liquid discharge pipe 140, and a dye solution recovery pipe142, the rinse solution recovery pipe 128 and the leading end of a drainpipe 144 are connected to three output ports of the switching unit 138,respectively.

The dry unit includes a dry gas supply source 146 including, forexample, a warm blast generator or a blow fan, and is configured to becapable of pumping dry gas (e.g., air and nitrogen gas) at apredetermined flow rate to the nozzle 20 through the gas supply line148, the switching unit 134, and the fluid supply line 136. Anopen/close valve 150 is provided on the way of the gas supply line 148.

As in the exemplary embodiment 1, the controller 82 includes amicrocomputer and an interface as needed, controls each unit in the dyeadsorption device (dye adsorption unit, rinse unit and dry unit), andfurther controls the sequence of the entire apparatus for executing adye adsorption step, a rinse step, and a dry step.

In the substrate treatment apparatus, the dye adsorption step, the rinsestep and the dry step are sequentially performed for the treatedsubstrate G placed on the chuck plate 14 of the substrate holding unit12 within the processing chamber 10.

The dye adsorption step is executed by the dye adsorption unit under thecontrol of the controller 82. In such a case, the inlet side of thefirst switching unit 134 is switched to the dye solution supply line 40and the outlet side of the second switching unit 138 is switched to thedye solution recovery pipe 142. As in the dye adsorption processing inthe first exemplary embodiment, the dye solution from the dye solutionsupply unit 32 is sent to the nozzle 20 at a predetermined flow rate andthe dye solution from the slit-like ejection ports 88L, 88R is ejectedonto the substrate G which is rotated integrally with the chuck plate14. As such, the dye solution is compressively contacted with thetreated surface (porous semiconductor layer 204) of the substrate G at apredetermined impact force, and further whirlpool or turbulent flow isgenerated in the vertical direction in the flow of the dye solution inthe groove-like uneven sections 94L, 94R of the solution guide surfaces92L, 92R of the nozzle 20, thereby increasing the contact pressure ofthe dye solution in relation to the treated surface (poroussemiconductor layer 204) of the substrate G. Thus, aggregation orcohesion of the dye is hardly caused on the surface layer portion of theporous semiconductor layer 204, the dye effectively penetrates deeplyinto the porous semiconductor layer 204, and the dye adsorption into theporous semiconductor layer 204 proceeds at a high speed.

As a predetermined time elapses after starting the dye adsorption step,the dye adsorption unit (especially, the dye solution supply unit 32,the dye solution recovery unit 34 and the driving unit 18 of thesubstrate holding unit 12) is stopped so that the dye adsorption step isended. Next, the rinse unit starts the rinse step in a state where thenozzle 20 is fixed to the processing position P₁. At this time, theinlet side of the first switching unit 134 is switched to the rinsesolution supply line 116. In addition, the open/close valve 64 isopened, and suction pump 58 and the electromagnetic proportion valve 62are operated. However, just after starting the rinse step, the outletside of the second switching unit 138 is left connected to the dyesolution recovery pipe 142.

In the rinse step, the rinse solution from the rinse solution supplyunit 110 is sent to the nozzle 20 at a predetermined flow rate, and therinse solution is ejected from slit-like ejection ports 88L, 88R of thenozzle 20 to the top side of the substrate G which is rotated integrallywith the chuck plate 14. As such, a flow of the rinse solution is formedin the gap between the guide surfaces 92L, 92R of the nozzle 20 and thesubstrate G, and the porous semiconductor layer 204 of the treatedsurface of the substrate is subject to rinse processing in such flow ofthe rinse solution. With this rinse processing, extra dye or dyesolution adhered to or remaining on the surface of the poroussemiconductor layer 204 is promptly washes off.

When the extra dye or dye solution adhered to or remaining on thesurface of the porous semiconductor layer 204 by the dye adsorption stepis left as it is, there is a concern that the dye coheres andprecipitates and thus, photovoltaic conversion efficiency may decrease.In the present exemplary embodiment, the extra dye is removed from thesurface of the porous semiconductor layer 204 by the rinse processing asdescribed above. Therefore, the cohesion and precipitation of the dye onthe surface layer portion of the porous semiconductor layer 204 may beeffectively avoided. Thus, the efficiency, reproducibility and stabilityof photovoltaic conversion in a dye sensitization solar cell may beenhanced.

In the present exemplary embodiment, since the outlet side of the secondswitching unit 138 is in the state where it is switched to the dyesolution recovery pipe 142 just after starting the rinse step or in theinitial stage, the used rinse solution (recovered solution) mixed withthe dye solution discharged from the outlet ports 36L, 36R of the nozzle20 is sent to the dye solution recovery unit 34 through the vacuum line60, the second switching unit 138 and the dye solution recovery pipe 14.The dye solution recovery unit 34 produces a regenerated dye solutionfrom the recovered solution which is mixed with the dye solution, andsends the regenerated dye solution to the tank 38 of the dye solutionunit 32 (FIG. 1).

However, the dye solution mixed in the recovered solution is graduallydiluted as the rinse step proceeds. Thus, after the middle stage of therinse step, the outlet side of the second switching unit 138 is switchedto the rinse solution recovery pipe 128 and the recovered solution issent to the rinse solution recovery unit 112. Alternatively, the outletside of the second switching unit 138 may be switched to the drain pipe144 in the middle stage of the rinse step and switched to the rinsesolution recovery pipe 128 only in the late state of the rinse step.

After the lapse of predetermined processing time from the start of therinse step, the rinse unit (especially, the rinse solution supply unit110, the rinse solution recovery unit 112 and the driving unit 18 of thesubstrate holding unit 12) is stopped to end the rinse step. Next, thedry unit starts the dry step in a state where the nozzle 20 is fixed tothe processing position P₁. In such a case, the inlet side of the firstswitching unit 134 is switched to the gas supply line 148 and theopen/close valve 150 is opened. Meanwhile, the open/close valve 64 of adye solution/rinse solution recovery system is left closed. However, theexhaust of the inside of the processing chamber 10 is continued byoperating the suction pump 58 in the state where the open/close valve 76is opened. The outlet side of the second switching unit 138 is switchedto the drain pipe 144.

In the dry step, dry gas is sent from the dry gas supply source 146 tothe nozzle 20 at a predetermined flow rate, and the dry gas is injectedfrom slit-like ejection ports 88L, 88R of the nozzle 20 to the treatedsurface of the substrate G which is rotated integrally with the chuckplate 14. Thus, the rinse solution adhered to the treated surface of thesubstrate G is blown away by the gas stream from the nozzle 20 and thus,the treated surface of the substrate G is dried.

After a predetermined processing time elapses after starting the drystep, the dry unit (especially, the dry gas supply source 146, thesuction pump 58 and the driving unit 18 of the substrate holding unit12) is stopped and thus, the dry step is ended. Just after this, thenozzle movement mechanism 22 is operated to move the nozzle 20 from theprocessing position P₁ above the chuck plate 14 to the standby positionP₂ above the nozzle standby unit 26. The substrate holding unit 12releases the adsorptive holding of the substrate G on the chuck plate 14and lifts the substrate G upward from the chuck plate 14 by the lift pinmechanism to hand the substrate G over to the transport robot.

As described above, the substrate treatment apparatus of the presentexemplary embodiment includes the dye adsorption device of the firstexemplary embodiment and thus, may significantly reduce the timerequired for the treatment of adsorbing sensitizing dye into a poroussemiconductor layer on a substrate. By being provided with a rinse unit,the substrate treatment apparatus performs rinse processing just afterthe dye adsorption processing to remove extra dye from surface layerportion of the substrate and effectively prevent or suppress thecohesion and precipitation of the dye, thereby enhancing the efficiency,reproducibility and stability of photovoltaic conversion.

Also, since the nozzle 20 used in the sensitizing dye adsorptionprocessing is used as a post-treatment nozzle, i.e. as a rinse nozzlefor rinsing and further as for a dry gas nozzle as it is, the substratetreatment apparatus of the present exemplary embodiment may facilitatethe simplification and cost reduction of the entire apparatus as well asthe efficiency and time shortening for the entire composite treatments.

In addition, in the exemplary configuration of FIG. 8, the rinsesolution supply unit 110 is provided with the dedicated supply pump 120and the proportion valve 122. However, the supply pump 44 and theproportion valve 46 of the dye solution supply unit 32 may be used asthe supply pump 120 and the proportion valve 122, respectively.

Further, although not illustrated, a rinse-only nozzle or a dry-onlynozzle may be provided separately from the dye adsorption processingnozzle 20. As for such a rinse-only nozzle or dry-only nozzle, anynozzle well-known or known to public in the related art may be used.However, a separate nozzle with the same construction as the sensitizingdye adsorption processing-only nozzle 20 may be used. Accordingly, whendifferent nozzles are used for different treatments, for example, thesubstrate holding unit 12 the processing chamber 10 in each treatmentmay be different from those in any other treatment. In addition, in thedry step, solution removal (dry) from the treated surface of a substrateG may be performed, for example, by rotating the substrate G integrallywith the chuck plate 14 without using any nozzle.

Other Exemplary Embodiments or Modified Embodiments

Although several exemplary embodiments have been described above, thepresent invention is not limited to the above-described exemplaryembodiments and other embodiments or various modifications may be madewithin the sprit and scope of the present invention.

For example, the cross-sectional shape of the groove-like unevensections 94L, 94R of the nozzle 20 may be formed in a shape other thanthe quadrilateral shape, for example, in a triangular shape asillustrated in FIGS. 9A and 9B. Also in such a case, in order to causeturbulent flow of the dye solution (or the rinse solution) to beefficiently, stably and securely generated in the groove-like unevensections 94L, 94R, the ranges of W=0.3S_(a) to 1.5S_(a) and D=0.3S_(a)to 1.5S_(a) are preferable, and the ranges of W=0.5S_(a) to 1.0S_(a) andD=0.5S_(a) to 1.0S_(a) are most preferable, in which W is the width ofthe inlets of the groove-like uneven sections 94L, 94R and D is thedepth of the groove-like uneven sections 94L, 94R.

As illustrated in FIG. 10, the ejection passages 86L, 86R and theejection ports 88L, 88R of the nozzle 20 may also be formed by aplurality of fine holes (tunnels) arranged at a predetermined pitch inthe longitudinal direction. Such porous ejection ports have an advantagein that they may further increase ejecting pressure (impact force)against the substrate G.

The groove-like uneven sections 94L, 94R of the nozzle 20 are notlimited to the construction in which concave portions are deeply formedin relation to the guide surfaces 92L, 92R and may be configured suchthat convex portions protrude to the gap sides in relation to the guidesurfaces 92L, 92R as illustrated in FIG. 11.

Also, as illustrated in FIG. 12, an ejection port 84, a guide surface92, a groove-like uneven section 94 and a suction port 96 of a singleline may be provided in the nozzle 20. In such a case, the substratemovement at each position on the substrate G may be always maintained inthe forward direction or reverse direction in relation to the flow ofthe dye solution on the substrate G. Accordingly, when the substratemovement direction (rotation direction) in the reverse direction isselected, the relative flow velocity of the dye solution (or the rinsesolution) may be increased at each position on the substrate G.

As another exemplary embodiment, as illustrated in FIGS. 13A and 13B,the groove-like uneven sections 94L, 94R may be omitted from the guidesurfaces 92L, 92R of the nozzle 20. As described above, the groove-likeuneven sections 94L, 94R of the nozzle 20 greatly contribute to thespeedup of the dye solution treatment by generating whirlpool orturbulent flow in the flow of dye solution (or rinse solution) on thesubstrate G. Accordingly, omission of the groove-like uneven sections94L, 94R may decrease the efficiency of the dye adsorption processing(or rinse processing) and increase processing time by the extent thatmay be obtained with the groove-like uneven sections 94L, 94R. However,in comparison with the conventional dipping method, the efficiency ofthe dye adsorption processing is exceptionally high and processing timeis remarkably shortened due to the flow and ejecting pressure (impactforce) of the dye solution.

In still another exemplary embodiment, as illustrated in FIGS. 14A and14B or FIGS. 15A and 15B, the suction sections 30L, 30R may be omittedfrom the nozzle 20. In such a case, omission of the suction sections30L, 30R may slacken the flow of dye solution (or rinse solution) on thesubstrate G, decrease the efficiency of dye adsorption processing (orrinse processing), and increase a processing time by the extent that maybe obtained with the suction sections 30L, 30R. However, in comparisonwith the conventional dipping method, the efficiency of dye adsorptionprocessing is high and processing time is shortened.

Also, the loss caused by the omission of the level suction section 30L,30R may be replenished by variably controlling the ejecting pressure orejecting flow rate of the nozzle 20. That is, when the suction sections30L, 30R are not provided, the flow of the dye solution on the substrateG is slackened and thus, the dye adsorption efficiency may be decreasedas the processing time elapses. Thus, as illustrated in FIG. 16A, it maybe proper to employ a method of increasing the ejecting pressure (orejecting flow rate) of the nozzle 20 step by step as time passes throughthe electromagnetic proportion valves 46, 62 at a time interval(preferably, the later half) or over the entire time interval (T=0 toT=T_(E)) in the processing time.

In addition, in one of the above-described exemplary embodiments, thesubstrate G is rotated in the azimuthal direction during the processingon the substrate holding unit 12. In another exemplary embodiment, itmay also be possible repeatedly reciprocate the nozzle 20 at constantcycle in the horizontal direction (X direction) orthogonal to thelongitudinal direction of the nozzle 20 (Y direction) by operating thenozzle movement mechanism 22. In such a case, when the whole length ofthe nozzle 20 (ejection port 88) is set to correspond to the length ofthe substrate in the longitudinal direction of the nozzle 20 (Ydirection), the opposite ends of the nozzle 20 (ejection port 88) maynot protrude to the outside of the substrate G (that is, the dyesolution may be completely suppressed from scattering to thesurroundings).

Alternatively, as illustrated in FIG. 17, the nozzle 20 may beconfigured to have a size much larger than that of the substrate G notonly in the longitudinal direction of the nozzle 20 (Y direction) butalso in the widthwise direction of the substrate G (X direction) so thatthe nozzle 20 may completely cover the substrate G. In such a case, dyeadsorption processing may be performed in a state where the nozzle 20and the substrate G are both stopped.

Also, in another exemplary embodiment, as illustrated in FIG. 18, thenozzle 20 may be configured in a disc shape. In such a case, the nozzle20 includes a circular ejection port 88, a circular guide surface 92,circular groove-like uneven sections 94, and a circular suction port 96which are concentric to each other.

In addition, although not illustrated, the uneven sections 94(94L, 94R)may be formed in a type other than the groove type, for example, in adimple type.

Further, in another exemplary embodiment in which a relative movement isperformed between the nozzle 20 and substrate G, as illustrate in FIG.19, it may be possible to provide a configuration that stops the nozzle20 and rectilinearly moves or reciprocates the substrate G in thehorizontal direction (X direction) orthogonal to the longitudinaldirection of the nozzle (20) (Y direction). In such a case, as a meansfor holing and horizontally moving the substrate G, for example, acarrying type or floating type stage or a conveyer may be used.

Also, although not illustrated, the suction sections 30(30L, 30R) may beconfigured to be independent from the nozzle 20. Accordingly, thesuction ports 96(96L, 96R) of a suction sections 30(30L, 30R) of aseparate member may be arranged, for example, both sides (or one side)of the nozzle 20 to be spaced apart from the nozzle 20.

The present invention may be properly applied to a step of adsorbingsensitizing dye into a porous semiconductor layer of a dye sensitizationsolar cell as described above. However, the present invention may alsobe applied to a treatment of adsorbing any dye into any thin film formedon a surface of a substrate.

DESCRIPTION OF SYMBOLS

-   -   10: processing chamber        -   12: substrate holding unit        -   22: nozzle movement mechanism        -   26: standby bus        -   28: ejection section    -   30L, 30R: suction section    -   32: solution supply unit    -   34: solution recovery unit    -   40: dye solution supply line    -   46, 62: electromagnetic proportion valve    -   60: vacuum line    -   86L, 86R: ejection passage    -   88L, 88R: ejection port    -   92L, 92R: solution guide surface    -   94L, 94R: groove-like uneven section    -   96L, 96R: suction port    -   110: rinse solution supply unit    -   112: rinse solution recovery unit    -   134, 138: switching unit    -   146: dry gas supply source

1. A dye adsorption apparatus of adsorbing a dye into a poroussemiconductor layer formed on a treated surface of a substrate, theapparatus comprising: a holding unit configured to hold the substratesuch that the treated surface of the substrate faces upward; a nozzlehaving an ejection port and disposed above the holding unit so that theejection port faces downward; and a dye solution supply unit configuredto pump a dye solution formed by solving the dye in a predeterminedsolvent to the nozzle, wherein the dye solution is ejected from theejection port of the nozzle to the treated surface of the substrate heldon the holding unit through a first gap so that a flow of the dyesolution is formed on the treated surface of the substrate and the dyecontained in the dye solution is adsorbed into the semiconductor layer.2. The apparatus of claim 1, further comprising: a movement mechanismconfigured to cause a relative movement to be performed between thesubstrate on the holding unit and the nozzle in parallel to thesubstrate, wherein the ejection port of the nozzle is formed in a slitshape, and the flow of the dye solution is formed in a directionintersecting the extending direction of the slit.
 3. The apparatus ofclaim 1, further comprising: a movement mechanism configured to cause arelative movement to be performed between the substrate on the holdingunit and the nozzle in parallel to the substrate, wherein the ejectionport has a plurality of ejection holes arranged in a predetermineddirection at a predetermined pitch, and the flow of the dye solution isformed in a direction intersecting the arrangement direction of theejection holes.
 4. The apparatus of claim 1, wherein a guide surfaceopposed to the treated surface of the substrate through a second gap isformed around or next to the ejection port of the nozzle, and the flowof the dye solution is formed along the guide surface.
 5. The apparatusof claim 4, further comprising: a suction section positioned at atrailing end of the flow of the dye solution on the substrate andconfigured to suck in the dye solution.
 6. A dye adsorption method ofadsorbing dye into a porous semiconductor layer formed on a treatedsurface of a substrate, the method comprising: disposing the substrateat a predetermined position such that the treated surface of thesubstrate faces upward; positioning the nozzle to be opposed to thesubstrate; and pumping dye solution formed by solving the dye in apredetermined solvent to the nozzle and ejecting the dye solution fromthe ejection port of the nozzle to the treated surface of the substrateheld on the holding unit through a first gap so that a flow of the dyesolution is formed on the treated surface of the substrate and the dyecontained in the dye solution is adsorbed into the semiconductor layer.7. The method of claim 6, further comprising causing a relative movementto be performed between the substrate and the nozzle in parallel to thesubstrate during the processing, wherein the flow of dye solution isformed in a surface parallel to the substrate in a directionintersecting the extending direction or distributed direction of theejection port.
 8. The method of claim 6, wherein the flow of the dyesolution is formed along a guide surface of the nozzle which is opposedto the treated surface of the substrate through a second gap around ornext to the ejection port of the nozzle.
 9. The method of claim 8,wherein the dye solution forms turbulent flow by an unevenness sectionformed on the guide surface.
 10. The method of claim 8, wherein the dyesolution is sucked in at a trailing end of the flow of the dye solution,thereby being recovered.
 11. The method of claim 6, wherein the ejectingpressure or ejecting flow rate of the nozzle is varied during theprocessing.
 12. The method of claim 11, wherein the ejecting pressure orejecting flow rate of the nozzle is increased linearly as time passesover an interval or the entire interval in processing time.
 13. Themethod of claim 11, wherein the ejecting pressure or ejecting flow rateof the nozzle is increased step by step during the processing.
 14. Asubstrate treatment apparatus comprising: a holding unit configured tohold a substrate formed with a porous semiconductor treated surface suchthat the treated surface faces upward; a dye adsorption unit configuredto adsorb dye to the semiconductor layer of the substrate held on theholding unit; a rinse unit configured to wash out extra dye from asurface of the semiconductor layer of the substrate, wherein the dyeadsorption unit includes: a first nozzle having an ejection port anddisposed above the holding unit such that the ejection port facesdownward, and a dye solution supply unit configured to pump dye solutionin which the dye is solved in a predetermined solvent to the firstnozzle, and wherein the dye solution is ejected from the ejection portof the nozzle to the treated surface of the substrate held on theholding unit through a first gap so that a flow of the dye solution isformed on the treated surface of the substrate and the dye contained inthe dye solution is adsorbed into the semiconductor layer.
 15. Theapparatus of claim 14, further comprising: a movement mechanismconfigured to cause a relative movement to be performed between thesubstrate on the holding unit and the first nozzle in parallel to thesubstrate, wherein the ejection port of the first nozzle is formed in aslit shape, and the flow of the dye solution is formed in a directionintersecting the extending direction of the slit.
 16. The apparatus ofclaim 14, further comprising: a movement mechanism configured to cause arelative movement to be performed between the substrate on the holdingunit and the first nozzle in parallel to the substrate, wherein theejection port has a plurality of ejection holes arranged in apredetermined direction at a predetermined pitch, and the flow of thedye solution is formed in a direction intersecting the arrangementdirection of the ejection holes.
 17. The apparatus of claim 14, whereina guide surface opposed to the treated surface of the substrate througha second gap is formed around or next to the ejection port of thenozzle, and the flow of the dye solution is formed along the guidesurface.
 18. The apparatus of claim 14, further comprising: a suctionsection positioned at a trailing end of the flow of the dye solution onthe substrate and configured to suck in the dye solution.
 19. Theapparatus of claim 14, wherein the ejecting pressure or ejecting flowrate of the nozzle is variable during the processing.
 20. The apparatusof claim 19, wherein the ejecting pressure or ejecting flow rate of thenozzle is increased linearly as time passes over an interval or theentire interval of processing time.
 21. The apparatus of claim 19,wherein the ejecting pressure or ejecting flow rate of the nozzle isincreased step by step during the processing.